The present invention relates to multi-stage hydrodynamic pumps and in particular to the construction of the diffuser guide vanes therefor.
Multi-stage hydrodynamic centrifugal pumps are formed with a succession of impellers, separated by interstage channels which cause the liquid from one impeller to be carried to the succeeding impeller. In the known construction of centrifugal pumps, the liquid after leaving the first impeller enters a radially centrifugal, or a radially-axial vane diffuser. After leaving the diffuser the liquid flows through an annular vaneless section, the inlet and outlet portions of which are, in the radial design both curved or bent, while in the radial axial design the inlet portion is straight and only the outlet portion is curved or bent. From this vaneless section, the liquid flows into a guide channel provided with directional vanes which deflect and change the flow of the liquid so that it leaves the channel at an angle approaching 90.degree. with respect to the circumferential direction, so that it would enter the second impeller in a general axial direction. In some constructions, the centrifugal vane diffuser is connected directly with the vaned guide channel so as to form a single unit, omitting thereby the vaneless section. In any event the known constructions of multi-stage pumps, with the conventional diffusers, have the disadvantage in that they require the pump to have a relatively large outer diameter, so that they may be adequately dimensioned for the movement of the liquid. In addition, such pumps employing the conventional diffusers, suffer from undesirable vibration, pulsation, and substantial instability of performance characteristics.
It is the object of the present invention to provide a multi-stage hydrodynamic pump having an improved diffuser guide vane construction which overcomes the defects and disadvantages of the prior art.
It is a further object of the present invention to provide an improved construction and configuration for the guide vanes of a diffuser for a hydrodynamic multi-stage pump which provides greater operating efficiency, reduction of vibration as well as increased stability of performance characteristics.
The foregoing objects, other objects and advantages will be apparent from the following disclosure of the present invention.